Scott Disick, 35, and Sofia Richie, 19, have reportedly just broken up, and apparently it was her that did the dumping, according to Us Weekly. “Sofia and Scott split up,” a source tells the outlet. “He cheated on her in Miami and she found out and told [her father] Lionel [Richie]. He said he is going to cut her off and write her out of his will if she continues her relationship with Scott as he thinks he’s extremely toxic for her.” Whoa!

He allegedly cheated on her “after their trip to St. Bart’s and it caused huge problems in their relationship,” the source tells Us. “He went to Wyoming because of it and was photographed with another girl and that was the icing on the cake for her to break up with him.” Fan’s will remember, Scott headed to the Midwest for Kanye West‘s album release party on Thursday, May 31. That’s when he was spied with his hands all over another woman.

Apparently he was “really sloppy throughout the night” and “could barely speak,” according to the mag. He was also apparently telling people that he was “single,” via TMZ. Afterwards, we learned that Scott was begging Sofia not dump him over the incident. “Scott and Sofia had a big fight before he left for Wyoming, she was not invited to Kanye’s listening party and was hurt that Scott would go without her,” an insider told HollywoodLife.com EXCLUSIVELY. “But they did not break up before he left, and as of now they are still together.”

Guess we know why they had such an epic fight before he took off for Wyoming now. But is Sofia’s father’s disapproval enough to make this make this breakup stick? Stayed tuned for more on this developing story…